A deflection element described in Patent Literature 1 includes a sheet-like first transparent electrode, a liquid crystal layer, and a sheet-like second transparent electrode. A pair of first terminals are formed along respective opposite ends of the first transparent electrode in an up-down direction. A pair of second terminals are formed along respective opposite ends of the second transparent electrode in a left-right direction.
When a first voltage is applied to one first terminal of the pair of first terminals and a second voltage different from the first voltage is applied to the other first terminal in order to deflect light downwards, an electric potential gradient linearly varying from the one first terminal to the other first terminal is formed in the first transparent electrode since the first transparent electrode is a highly resistive film. Therefore, refractive index distribution corresponding to the electric potential gradient in the first transparent electrode is formed in the liquid crystal layer. As a result, exiting light is deflected downwards.